1. Field of the Invention
This invention relates to hydrocarbon recovery systems and particularly to hydrocarbon recovery systems for use in broken ice conditions.
2. Description of the Prior Art
Current mechanical response technology for oil spill response, when used in icy and rough ocean conditions is ineffective. Booms and skimmers simply do not function in common Arctic and Antarctic ice conditions. Small ice floes can perforate even the strongest boom materials, and skimmers require calm conditions to perform with very low actual recovery.
Changing ocean ice and steadfast ice conditions now create unpredictable ice flow movement as multiyear ice packs to thin. Evolving polar climates create ice conditions that behave increasingly erratic, complicating oil spill response recovery even further.
At present, most devices for dealing with oil spills on ice deal with oil on the surface or within a floe or block of ice, rather than conditions where oil in liquid water that is mixed with ice. Some examples of these devices are found in the following U.S. Pat. No. 6,592,765, which teaches a device that forces ice blocks under the water to cause the oil to float off the ice using vibration. U.S. Pat. No. 8,343,358, uses a three-hulled vessel to push ice blocks under the vessel where scrapers shave off the top layers of oil-containing ice. U.S. Pat. No. 7,112,279 uses a different approach. Here, a vessel has an opening in the side that collects oil, water and ice. Once in the vessel, the oil is separated and contained. Another alternative is found in U.S. Pat. No. 4,053,406, which discloses a vessel that picks up whole blocks of surface ice, cleans them and the returns them to the water. U.S. Pat. No. 4,039,454 teaches a device jars ice pieces while at the same time propels them back away from the oil pickup section. The ice chunks are then upwardly propelled along the inclined surface of a perforated inclined throughput barrier, which allows oil jarred from the ice to rise through the barrier and toward the surface of the water. The oil is contained and, in fact, “built up” in thickness above the through put barrier as a result of its being contained between the side support members of the structure supporting the pick-up device, the ‘pick-up device itself, and a rear “back stop”. U.S. Pat. No. 7,182,860 teaches a device that has a frame that is positioned on the surface of an ice/water mixture. Air is removed to cause the water level to rise within the frame. A disintegrator rotates within the frame to emulsify the oil so that it can be removed from the housing to a treatment vessel.
From the descriptions above, it is clear that these devices either work by picking up whole blocks of ice for cleaning, or by working the surface of the ice to remove oil. None of these devices works well in dealing with broken ice conditions where ice is not solidly packed into convenient blocks.